scop detection: do not run scop detection on regions without loops

otherwise, use -polly-detect-scops-in-regions-without-loops to also detect scops
in regions without loops

git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@183113 91177308-0d34-0410-b5e6-96231b3b80d8
scop detection: do not call getAliasSetForPointer when IgnoreAliasing

Contributed-by: Dmitry N. Mikushin <maemarcus@gmail.com>

git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@183114 91177308-0d34-0410-b5e6-96231b3b80d8